Accessory

ABSTRACT

An accessory that can be attached to a camera body, the camera body including a first camera-side clock terminal that outputs a first clock signal, a second camera-side clock terminal to which a second clock signal is input, and a first camera-side power supply terminal that outputs first power, the accessory includes: an eighth terminal that is brought into contact with the first camera-side clock terminal; a tenth terminal that is brought into contact with the second camera-side clock terminal; and a second terminal that is brought into contact with the first camera-side power supply terminal, wherein: a distance between the tenth terminal and the second terminal is longer than a distance between the eighth terminal and the second terminal.

INCORPORATION BY REFERENCE

The disclosure of the following priority application is hereinincorporated by reference: Japanese Patent Application No. 2017-207119filed Oct. 26, 2017

TECHNICAL FIELD

The present invention relates to an accessary.

BACKGROUND ART

There have been known accessories that can be removably attached to acamera body (for example, see PTL1). The accessories have heretoforebeen required to be attached to a camera body in a properly useablemanner.

CITATION LIST Patent Literature

PTL1: Japanese Laid-Open Patent Publication No. 2004-117380

SUMMARY OF INVENTION

According to the first aspect of the present invention, an accessorythat can be attached to a camera body, the camera body including a firstcamera-side clock terminal that outputs a first clock signal, a secondcamera-side clock terminal to which a second clock signal is input, anda first camera-side power supply terminal that outputs first power, theaccessory comprises: an eighth terminal that is brought into contactwith the first camera-side clock terminal; a tenth terminal that isbrought into contact with the second camera-side clock terminal; and asecond terminal that is brought into contact with the first camera-sidepower supply terminal, wherein: a distance between the tenth terminaland the second terminal is longer than a distance between the eighthterminal and the second terminal.

According to the second aspect of the present invention, an accessorythat can be attached to a camera body, the accessory comprises: a secondterminal to which first power supplied from the camera body is input; afifth terminal to which a second ground potential for a second powersupplied from the camera body is input; an eighth terminal to which afirst clock signal from the camera body is input; and a tenth terminalto which a second clock signal from the camera body is input, wherein adistance between the tenth terminal and the second terminal is longerthan a distance between the eighth terminal and the second terminal.

According to the third aspect of the present invention, an accessorythat can be attached to a camera body, the accessory comprises: a secondterminal to which first power supplied from the camera body is input; afifth terminal to which a second ground potential for a second powersupplied from the camera body is input; and an eighth terminal to whicha first clock signal from the camera body is input; and a tenth terminalthat outputs a second clock signal to the camera body, wherein adistance between the tenth terminal and the second terminal is longerthan a distance between the fifth terminal and the second terminal.

According to the fourth aspect of the present invention, an accessorythat can be attached to a camera body, the accessory comprises: a secondterminal to which first power supplied from the camera body is input; afifth terminal to which a second ground potential for a second powersupplied from the camera body is input; an eighth terminal to which afirst clock signal from the camera body is input; and a tenth terminalthat outputs a second clock signal to the camera body, wherein adistance between the eighth terminal and the second terminal is longerthan a distance between the fifth terminal and the second terminal.

According to the fifth aspect of the present invention, an accessorythat can be attached to a camera body, the camera body including asecond camera-side clock terminal to which a second clock signal isinput, a first camera-side power supply terminal that outputs firstpower, a first camera-side ground terminal corresponding to the firstpower, a second camera-side power supply terminal that outputs a secondpower, and a second camera-side ground terminal corresponding to thesecond power, the accessory comprises: a tenth terminal that is broughtinto contact with the second camera-side clock terminal; a secondterminal that is brought into contact with the first camera-side powersupply terminal; and a fifth terminal that is brought into contact withthe second camera-side ground terminal, wherein a distance between thetenth terminal and the second terminal is longer than a distance betweenthe fifth terminal and the second terminal.

According to the sixth aspect of the present invention, an accessorythat can be attached to a camera body, the camera body including a firstcamera-side clock terminal that outputs a first clock signal, a firstcamera-side power supply terminal that outputs first power, a firstcamera-side ground terminal corresponding to the first power, a secondcamera-side power supply terminal that outputs a second power, and asecond camera-side ground terminal corresponding to the second power,the accessory comprises: an eighth terminal that is brought into contactwith the first camera-side clock terminal; a second terminal that isbrought into contact with the first camera-side power supply terminal;and a fifth terminal that is brought into contact with the secondcamera-side ground terminal, wherein a distance between the eighthterminal and the second terminal is longer than a distance between thefifth terminal and the second terminal.

According to the seventh aspect of the present invention, an accessorythat can be attached to a camera body, the camera body including asecond camera-side clock terminal to which a second clock signal isinput, a first camera-side power supply terminal that outputs firstpower, a first camera-side ground terminal corresponding to the firstpower, a second camera-side power supply terminal that outputs a secondpower, and a second camera-side ground terminal corresponding to thesecond power, the accessory comprises: a tenth terminal that is broughtinto contact with the second camera-side clock terminal; a secondterminal that is brought into contact with the first camera-side powersupply terminal; and a third terminal that is brought into contact withthe first camera-side ground terminal, wherein a distance between thetenth terminal and the second terminal is longer than a distance betweenthe third terminal and the second terminal.

According to the eighth aspect of the present invention, an accessorythat can be attached to a camera body, the camera body including a firstcamera-side clock terminal that outputs a first clock signal, a firstcamera-side power supply terminal that outputs first power, a firstcamera-side ground terminal corresponding to the first power, a secondcamera-side power supply terminal that outputs a second power, and asecond camera-side ground terminal corresponding to the second power,the accessory comprises: an eighth terminal that is brought into contactwith the first camera-side clock terminal; a second terminal that isbrought into contact with the first camera-side power supply terminal;and a third terminal that is brought into contact with the firstcamera-side ground terminal, wherein a distance between the eighthterminal and the second terminal is longer than a distance between thethird terminal and the second terminal.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 schematically illustrates a configuration of a camera system;

FIG. 2 is a circuit diagram schematically illustrating electricalconnections between a camera body and an interchangeable lens;

FIG. 3 is a timing chart illustrating an example of command datacommunication;

FIG. 4 is a timing chart illustrating examples of hot-linecommunication;

FIG. 5A is a front view schematically illustrating a mount surface ofthe camera body as viewed from the side of the interchangeable lens, andFIG. 5B is a front view schematically illustrating the camera body inthe that the mount of the camera body has been removed as viewed fromthe side of the interchangeable lens; and

FIG. 6 is a front view schematically illustrating a mount surface of theinterchangeable lens as viewed from the side of the camera body.

DESCRIPTION OF EMBODIMENTS First Embodiment

FIG. 1 schematically illustrates a configuration of a camera system 1according to the first embodiment. The camera system 1 includes a camerabody 2 and an interchangeable lens 3, which represents an example of anaccessary that can be removably attached to the camera body 2.

The interchangeable lens 3 includes a lens-side mount 31, a lens-sideterminal holding unit 32, a lens-side control unit 33, a lens-sidecommunication unit 34, a lens-side storage unit 35, an imaging opticalsystem 36, and a driving unit 37. The lens-side mount 31 and thelens-side terminal holding unit 32 will be described in detail later.

The lens-side control unit 33 is made up of components such as amicrocomputer and its peripheral circuits. The lens-side communicationunit 34 performs a data communication with the camera body 2, which willbe described later. The lens-side communication unit 34 is connected toboth lens-side terminals (as described later) provided on the lens-sideterminal holding unit 32 and the lens-side control unit 33. Thelens-side storage unit 35 is a nonvolatile storage medium. The lens-sidestorage unit 35 is connected to the lens-side control unit 33. Thelens-side storage unit 35 has pre-stored information such as apredetermined control program to be executed by the lens-side controlunit 33. The lens-side control unit 33 controls the interchangeable lens3 by reading and executing the control program from the lens-sidestorage unit 35.

The imaging optical system 36 focuses an image of a subject on animaging surface of the image sensor 27, which will be described later.An optical axis O of the imaging optical system 36 substantiallycoincides with the center of the lens-side mount 31 and a body-sidemount 21, which will be described later. The imaging optical system 36illustrated in FIG. 1 generally includes a lens 36 a, a focusing lens 36b, and a lens 36 c. The focusing lens 36 b is a lens for adjusting theimaging position for the image of the subject. The driving unit 37 isconnected to the lens-side control unit 33 and includes an actuator orthe like (not illustrated). The driving unit 37 moves the focusing lens36 b in the optical axis direction (+Z and −Z directions) by means ofthe actuator or the like.

The camera body 2 includes a body-side mount 21, a body-side terminalholding unit 22, a body-side control unit 23, a body-side communicationunit 24, a body-side storage unit 25, a power unit 26, an image sensor27, and a switch 28 for detecting the state of a lock pin, which will bedescribed later.

The body-side control unit 23 is made up of components such as amicrocomputer and its peripheral circuits. It will be noted that thebody-side control unit 23 controls various functions of a body, althoughonly communication-related functions are described herein and otherfunctions are omitted. The body-side communication unit 24 performs adata communication with the interchangeable lens 3, which will bedescribed later. The body-side communication unit 24 is connected toboth body-side terminals (which will be described later) provided on thebody-side terminal holding unit 22 and the body-side control unit 23.Some terminals of the body-side terminal holding unit 22 are connectedto the body-side control unit 23, as described later. The body-sidestorage unit 25 is a nonvolatile storage medium. The body-side storageunit 25 is connected to the body-side control unit 23. The body-sidestorage unit 25 has pre-stored information such as a predeterminedcontrol program to be executed by the body-side control unit 23. Thebody-side control unit 23 controls the camera body 2 by reading andexecuting the control program from the body-side storage unit 25.

The power unit 26 includes a power supply and supplies power within thecamera body 2 and to the interchangeable lens 3. The power unit 26 isconnected to both body-side terminals (which will be described later)provided to the body-side terminal holding unit 22 and the body-sidecontrol unit 23. The image sensor 27 is a solid-state image sensor suchas CCD and CMOS, for example. The image sensor 27 is connected to thebody-side control unit 23 and images a subject to output an imagingsignal. Description of processing on an output imaging signal isomitted.

FIG. 2 is a circuit diagram schematically illustrating electricalconnections between the camera body 2 and the interchangeable lens 3.The body-side terminal holding unit 22 includes an LDET (B) terminal, aVBAT (B) terminal, a PGND (B) terminal, a V33 (B) terminal, a GND (B)terminal, an RDY (B) terminal, a DATAB (B) terminal, a CLK (B) terminal,a DATAL (B) terminal, an HCLK (B) terminal, and an HDATA (B) terminal.These 11 pieces of body-side terminals are collectively referred to asbody-side terminal group.

The LDET (B) terminal is a terminal for detecting attachment anddetachment of the interchangeable lens 3. The LDET (B) terminal isconnected to the body-side control unit 23 through a resistor R2. Apower supply V33 from the power unit 26 is connected between thebody-side control unit 23 and the resistor R2 across a resistor R1 topull up the LDET (B) terminal.

The VBAT (B) terminal, the PGND (B) terminal, the V33 (B) terminal, andthe GND (B) terminal are power supply-related terminals connected to thepower unit 26. In FIG. 2, the direction of supplied power is indicatedby an arrow. The VBAT (B) terminal is a terminal used for supplyingpower to the interchangeable lens 3. The power supplied through the VBAT(B) terminal drives the driving unit 37 of the interchangeable lens 3.The driving unit 37 requires voltage and current larger than those tothe lens-side control unit 33 to operate and the voltage applied to theVBAT (B) terminal by the power unit 26 is around 10 V at the maximum. Inthe following description, the voltage applied to the VBAT (B) terminalby the power unit 26 is referred to as a driving system voltage. ThePGND (B) terminal is a corresponding ground terminal to the VBAT (B)terminal.

The V33 (B) terminal is a terminal used for supplying power to theinterchangeable lens 3. The power supplied through the V33 (B) terminalfrom the power unit 26 is used to operate the lens-side control unit 33and the like. The lens-side control unit 33 and the like units areoperated by voltage and current smaller than those to the driving unit37. The voltage applied to the V33 (B) terminal by the power unit 26 isaround 3.3 V at the maximum. The voltage applied to the V33 (B) terminalby the power unit 26 is referred to as a circuit-related voltage. TheGND (B) terminal is a corresponding ground terminal to the V33 (B)terminal.

The RDY (B) terminal is connected to the body-side communication unit24. The DATAB (B) terminal, the CLK (B) terminal, the DATAL (B)terminal, the HCLK (B) terminal, and the HDATA (B) terminal arecommunication-related terminals connected to the body-side communicationunit 24. The RDY (B) terminal, the DATAB (B) terminal, the CLK (B)terminal, and the DATAL (B) terminal are used for command datacommunication, which will be described later. The HCLK (B) terminal andthe HDATA (B) terminal are connected to the body-side communication unit24 and used for hot-line communication, which will be described later.In FIG. 2, the signal flow is indicated by an arrow. A potential on theRDY (B) terminal indicates whether or not the interchangeable lens 3 isready for command data communication. The DATAB (B) terminal is aterminal from which a data signal is output to the interchangeable lens3. The CLK (B) terminal is a terminal from which a clock signal isoutput to the interchangeable lens 3.

The DATAL (B) terminal is a terminal to which a data signal from theinterchangeable lens 3 is input.

The HCLK (B) terminal is a terminal to which a clock signal from theinterchangeable lens 3 is input. The HDATA (B) terminal is a terminal towhich a data signal from the interchangeable lens 3 is input.

The lens-side terminal holding unit 32 includes an LDET (L) terminal, aVBAT (L) terminal, a PGND (L) terminal, a V33 (L) terminal, a GND (L)terminal, an RDY (L) terminal, a DATAB (L) terminal, a CLK (L) terminal,a; DATAL (L) terminal, an HCLK (L) terminal, and an HDATA (L) terminal.These 11 pieces of lens-side terminals are collectively referred to aslens-side terminal group. Once the interchangeable lens 3 is attached tothe camera body 2, the body-side terminals and the lens-side terminalsare electrically connected to each other as illustrated by dashed linesin FIG. 2. Specifically, the LDET (B) terminal is connected with theLDET (L) terminal, the VBAT (B) terminal is connected with the VBAT (L)terminal, the PGND (B) terminal is connected with the PGND (L) terminal,the V33 (B) terminal is connected with the V33 (L) terminal, the GND (B)terminal is connected with the GND (L) terminal, the RDY (B) terminal isconnected with the RDY (L) terminal, the DATAB (B) terminal is connectedwith the DATAB (L) terminal, the CLK (B) terminal is connected with theCLK (L) terminal, the DATAL (B) terminal is connected with the DATAL (L)terminal, the HCLK (B) terminal is connected with the HCLK (L) terminal,and the HDATA (B) terminal is connected with the HDATA (L) terminal. Therole of each lens-side terminal is the same as that of a body-sideterminal in contact therewith, and thus the description is omitted.

The LDET (L) terminal is grounded through a resistor R3. Once the LDET(L) terminal contacts the LDET (B) terminal, the potential of the LDET(B) terminal is pulled down. The VBAT (L) terminal and the PGND (L)terminal are connected to the driving unit 37. Between the VBAT (L)terminal and the PGND (L) terminal, a so-called bypass capacitor C1 isconnected. The V33 (L) terminal and the GND (L) terminal are connectedto the lens-side control unit 33 and the like units. A bypass capacitorC2 is connected between the V33 (L) terminal and the GND (L) terminal.The RDY (L) terminal, the DATAB (L) terminal, the CLK (L) terminal, theDATAL (L) terminal, the HCLK (L) terminal, and the HDATA (L) terminalare respectively connected the lens-side communication unit 34.

Description of Command Data Communication

Communication performed such that once a control command (command) istransmitted from the body-side control unit 23 to the lens-side controlunit 33 of the interchangeable lens 3, control contents (control data)from the body-side control unit 23 and response contents (response data)from the lens-side control unit 33 are transmitted and received inparallel to each other is referred to as command data communication. Thecommand data communication is a full duplex communication. Through thebody-side communication unit 24 and the lens-side communication unit 34,the command data communication is performed by means of a digital datacommunication using the RDY (B) terminal, the RDY (L) terminal, theDATAB (B) terminal, the DATAB (L) terminal, the CLK (B) terminal, theCLK (L) terminal, the DATAL (B) terminal, and the DATAL (L) terminal.

With command data communication, the body-side control unit 23 transmitsand receives various information to and from the interchangeable lens 3through the body-side communication unit 24 and the lens-sidecommunication unit 34 by transmitting various control commands andcontrol contents to the interchangeable lens 3 and receiving responsecontents from the interchangeable lens 3. The control commandsreferenced herein include a transmission command for lens information,for example. Various information received from the interchangeable lens3 includes type information of the interchangeable lens 3, informationindicative of optical properties such as focal length of the imagingoptical system 36 and the like, for example. Various informationtransmitted to the interchangeable lens 3 includes control contents suchas an amount of drive of a lens, type information of the camera body 2and the like, for example. The control commands also include a drivecommand for the focusing lens 36 b and the like. Based on the commanddata communication, the lens-side control unit 33 receives variouscontrol commands from the body-side control unit 23, acquires variousinformation from the body-side control unit 23, and transmits variousinformation to the body-side control unit 23.

FIG. 3 is an example of timing chart illustrating timings of commanddata communication. First, the body-side control unit 23 verifies asignal level on the RDY (B) terminal at the beginning of the commanddata communication (T1). The signal level on the RDY (B) terminalindicates whether or not the lens-side control unit 33 is ready for thecommand data communication. The lens-side control unit 33 sets thesignal level (or potential) on the RDY (B) terminal to a high level(H-level) if it is not ready for the command data communication. Thelens-side control unit 33 sets the signal level (or potential) on theRDY (L) terminal to a low level (L-level) through the lens-sidecommunication unit 34 if it is ready for the command data communication.

At the beginning of the command data communication (T1), the body-sidecontrol unit 23 outputs a clock signal 401 through the body-sidecommunication unit 24 from the CLK (B) terminal if the signal level onthe RDY (B) terminal is at the low level (L-level). In other words, thebody-side control unit 23 transmits the clock signal 401 to thelens-side control unit 33 through the CLK (B) terminal and the CLK (L)terminal. A frequency repeating between high level and low level of theclock signal 401 in FIG. 3 is 8 MHz, for example. In synchronizationwith the clock signal 401, the body-side control unit 23 outputs abody-side command signal 402, control commands, from the DATAB (B)terminal. In other words, the body-side control unit 23 transmits thebody-side command signal 402 to the lens-side control unit 33 throughthe DATAB (B) terminal and the DATAB (L) terminal. The body-side commandsignal 402, which is commanded by switched high and low levels of DATABin FIG. 3, is a signal indicative of a control that the body-sidecontrol unit 23 commands the lens-side control unit 33 by means of thecommand data communication. For example, the body-side command signal402 may be a signal indicative of a request for type information of theinterchangeable lens 3 or may be a signal indicative of a command todrive the focusing lens 36 b.

Upon reception of the body-side command signal 402 through the lens-sidecommunication unit 34, the lens-side control unit 33 uses an errordetecting code (for example, checksum data) included in the body-sidecommand signal 402 to execute a checking process for checking for acommunication error in the body-side command signal 402. The lens-sidecontrol unit 33 then sets the signal level on the RDY (L) terminal tothe high level (H-level) (T2). The body-side control unit 23 does nottransmit the body-side command signal 402 if the signal level on the RDY(B) terminal is at the high level. The lens-side control unit 33 startsa first control process 404 based on a command from the receivedbody-side command signal 402.

Upon completion of the first control process 404, the lens-side controlunit 33 sets the signal level on the RDY (L) terminal to the low level(L-level) through the lens-side communication unit 34 (T3). In responseto the signal level on the RDY (B) terminal being set to the low level,the body-side control unit 23 outputs a clock signal 405 from the CLK(B) terminal. In other words, the body-side control unit 23 transmitsthe clock signal 405 through the CLK (B) terminal and the CLK (L)terminal to the lens-side control unit 33. In addition, the body-sidecontrol unit 23 does not transmit or receive a body-side data signal 406and a lens-side data signal 407, if the signal level on the RDY (B)terminal is at the high level.

In synchronization with the clock signal 405, the body-side control unit23 outputs a body-side data signal 406 from the DATAB (B) terminalthrough the body-side communication unit 24. In other words, thebody-side control unit 23 transmits the body-side data signal 406 to thelens-side control unit 33 through the DATAB (B) terminal and the DATAB(L) terminal. The body-side data signal 406 is a signal indicative of acontrol parameter for the body-side command signal 402. For example, inthe case where the body-side command signal 402 is a signal indicativeof a command to drive the focusing lens 36 b, the correspondingbody-side data signal 406 may be a signal indicative of the amount ofdrive of the focusing lens 36 b. Alternatively, the body-side datasignal 406 may be a signal indicative of information required by thelens-side control unit 33 in the command data communication, such astype information of the camera body.

Upon input of the clock signal 405 to the CLK (L) terminal, thelens-side control unit 33 outputs the lens-side data signal 407 from theDATAL (L) terminal in synchronization with the clock signal 405. Thelens-side data signal 407, which is indicated by switched high and lowlevels of DATAL in FIG. 3, is a signal transmitted by the lens-sidecontrol unit 33 to the body-side control unit 23 by means of the commanddata communication. For example, in the case where the body-side commandsignal 402 is a signal indicative of a request for type information ofthe interchangeable lens 3, the corresponding lens-side data signal 407may be a signal indicative of the type information of theinterchangeable lens 3.

Upon completion of the transmission of the lens-side data signal 407,the lens-side control unit 33 again sets the signal level on the RDY (L)terminal to the high level (T4). The lens-side control unit 33 starts asecond control process 408 (which will be described later) based on anindication from the received body-side data signal 406.

The first and second control processes 404 and 408 executed by thelens-side control unit 33 will now be described. For example,description will now be made as to the case where the received body-sidecommand signal 402 contains a request for particular information on theinterchangeable lens 3. As the first control process 404, the lens-sidecontrol unit 33 executes a process for generating requested informationas the lens-side data signal 407. The lens-side data signal 407generated in the first control process 404 is transmitted to thebody-side control unit 23 through the lens-side communication unit 34,the DATAL (L) terminal, the DATAL (B) terminal, and the body-sidecommunication unit 24.

For example, description will now be made as to the case where thereceived body-side command signal 402 contains a signal indicative of acommand to drive the focusing lens 36 b. As the first control process404, the lens-side control unit 33 executes a process for generating asignal indicative of the reception of the signal indicative of a commandto drive the focusing lens 36 b. The signal generated in the firstcontrol process 404 is transmitted as the lens-side data signal 407 tothe body-side control unit 23 through the lens-side communication unit34, the DATAL (L) terminal, the DATAL (B) terminal, and the body-sidecommunication unit 24. As the second control process 408, the lens-sidecontrol unit 33 executes a process for driving the focusing lens 36 b bythe amount of drive specified in the body-side data signal 406.

Upon completion of the second control process 408, the lens-side controlunit 33 sets the signal level on the RDY (L) terminal to the low levelthrough the lens-side communication unit 34 (T5).

Communication conducted in the above timings T1 to T5 constitutes oneperiod of the command data communication. In one period of the commanddata communication, the body-side command signal 402 and the body-sidedata signal 406 are transmitted by the body-side control unit 23. Inother words, a combination of the body-side command signal 402 and thebody-side data signal 406 constitutes one control data.

As described above, the lens-side control unit 33 receives control datafrom the body-side control unit 23 and transmits response data to thebody-side communication unit 24 in parallel. In other words, the commanddata communication is a so-called full duplex communication.

Description of Hot-Line Communication

There is provided another communication path on which data istransmitted in one direction from the lens-side control unit 33 of theinterchangeable lens 3 to the body-side control unit 23 of the camerabody 2, which is referred to as hot-line communication. The hot-linecommunication refers to data communication between the body-side controlunit 23 and the lens-side control unit 33 through the body-sidecommunication unit 24 and the lens-side communication unit 34 by meansof the HCLK (B) terminal, the HCLK (L) terminal, the HDATA (B) terminal,and the HDATA (L) terminal. The body-side control unit 23 acquiresinformation related to a state of the interchangeable lens 3 from thelens-side control unit 33 of the interchangeable lens 3 by means of thehot-line communication. The information related to a state of theinterchangeable lens 3 may be, for example, a position of the focusinglens 36 b, a position of an image blur correction lens (notillustrated), and a position of an aperture. The image blur correctionlens is a member that can be moved (driven) to contain componentsperpendicular to the direction of the optical axis, and the aperture isa member that can be moved (driven) to change the size of an openingthrough which light flux passes. In the hot-line communication, once acommand to start communication is transmitted from the camera body inthe command data communication, the lens-side control unit 33autonomously transmits lens data to the body-side control unit 23irrespective of (independently of) the command data communication untila command to end the communication is arrived.

FIG. 4 is a timing chart illustrating timings of hot-line communication.Upon reception of a command to start the hot-line communication from thebody-side control unit 23 of the camera body in the command datacommunication (T6), the lens-side control unit 33 executes a generationprocess 501. The generation process 501 refers to a process in which astate of a lens is acquired in a sampling frequency of, for example, 1ms and a lens signal 503 for the hot-line communication is generated.Upon completion of the generation of the lens signal 503 (T7), thelens-side control unit 33 outputs a clock signal 502 through thelens-side communication unit 34 from the HCLK (L) terminal. In otherwords, the clock signal 502 is transmitted to the body-side control unit23 through the HCLK (L) terminal and HCLK (B) terminal. A frequencyrepeating between high level and low level of the clock signal 502 inFIG. 4 is 8 MHz to 20 MHz, for example. Specifically, the frequency ofthe clock signal 502 in the hot-line communication is at the same levelas or higher than the frequency of the clock signal 401 in the commanddata communication.

The lens-side control unit 33 outputs the lens signal 503 (for example,information related to a position of the focusing lens 36 b) generatedin the generation process 501 through the lens-side communication unit34 from the HDATA (L) terminal in synchronization with the clock signal502. In other words, the lens-side control unit 33 transmits the lenssignal 503 to the body-side control unit 23 through the lens-sidecommunication unit 34, the HDATA (L) terminal, the HDATA (B) terminal,and the body-side communication unit 24. The lens signal 503, which isindicated by switched high and low levels of HDATA in FIG. 4, is asignal transmitted by the lens-side control unit 33 to the body-sidecontrol unit 23 by means of the hot-line communication. The output ofthe clock signal 502 and the lens signal 503 ends at a timing T8.

The lens-side control unit 33 repeats the transmission of the lens datain the hot-line communication every certain period (for example, forevery 1 ms) until a command to end the transmission of the lens signal503 is received by means of the command data communication.

All or a part of the command data communication and the hot-linecommunication can be performed in parallel. In other words, thebody-side control unit 23 and the lens-side control unit 33 can start orend the hot-line communication during the command data communication.Similarly, they can start or end the command data communication duringthe hot-line communication.

As described above, in the hot-line communication, the communication isperformed independently of the command communication. The lens-sidecontrol unit 33 transmits information related to a state of theinterchangeable lens 3 to the body-side control unit 23 irrespective ofthe command communication by means of the hot-line communication.Consequently, the body-side control unit 23 can continuously grasp thestate of the interchangeable lens 3 even during the commandcommunication. In this way, the body-side control unit 23 cancontinuously grasp the position of the focusing lens 36 b, and thus cancontrol auto-focusing at high speed, for example. The same applies to animage blur correction control and an aperture control. The body-sidecontrol unit 23 can provide various commands for the interchangeablelens 3 by means of the command communication in any timing even whilethe lens-side control unit 33 is performing the hot-line communication.

Description of Lens Mount Mechanism

The camera system 1 according to the present embodiment includes a lensmount mechanism of a so-called bayonet type. Description will now bemade as to a body-side mount 21 on the camera body 2 and a lens-sidemount 31 on the interchangeable lens 3 in order.

FIG. 5A schematically illustrates a mount of the camera body 2 as viewedfrom the side of the interchangeable lens 3. The camera body 2 includesthe body-side mount 21 and the body-side terminal holding unit 22 asdescribed with reference to FIG. 1. The body-side mount 21 has areference plane of a ring shape that has a constant width. The body-sidemount 21 also includes a first body-side claw (or tab) 29 a, a secondbody-side claw 29 b, a third body-side claw 29 c, and a fourth body-sideclaw 29 d. In the following description, these four claws arecollectively referred to as body-side claws 29.

The body-side claws 29 are spaced apart from each other along a circularopening in the body-side mount 21. As illustrated in FIG. 5A, the firstbody-side claw 29 a is located at an upper right position, the secondbody-side claw 29 b is located at an upper left position, the thirdbody-side claw 29 c is located at a lower left position, and the fourthbody-side claw 29 d is located at a lower right position.

The length of each of the first to fourth body-side claws 29 a to 29 din a circumferential direction is different from each other.Specifically, the first body-side claw 29 a is the longest, the thirdbody-side claw 29 c is the second longest, the fourth body-side claw 29d is the third longest, and the second body-side claw 29 b is theshortest.

The body-side claws 29 protrude from the body-side mount 21 toward thecenter of the opening and there are sections with body-side claws 29 andsections without body-side claws 29 on the circumstance of the opening.In the following description, a space 40 a between the first body-sideclaw 29 a and the fourth body-side claw 29 d on the circumstance of theopening in the body-side mount 21 is referred to as a first body-sidethrough section (insertion/extraction section) 40 a. Similarly, a space40 b between the first body-side claw 29 a and the second body-side claw29 b is referred to as a second body-side through section 40 b, a space40 c between the second body-side claw 29 b and the third body-side claw29 c is referred to as a third body-side through section 40 c, and aspace 40 d between the third body-side claw 29 c and the fourthbody-side claw 29 d is referred to as a fourth body-side through section40 d. These four body-side through sections are collectively referred toas body-side through sections 40.

In the inside of the opening of the body-side mount 21, the body-sideterminal holding unit 22 is located. The body-side terminal holding unit22 has an arc shape corresponding to the shape of the ring-shapedbody-side mount 21. Preferably, the body-side terminal holding unit 22is located on an upper portion of the opening in the body-side mount 21along the opening in the body-side mount 21, in the center of the upperportion as illustrated in FIG. 5A. The body-side terminal holding unit22 includes a plurality of body-side terminals as described above. Theplurality of body-side terminals are arranged in the body-side terminalholding unit 22 in arc shape in one line inside the body-side mount 21.As illustrated in FIG. 5A, the plurality of body-side terminals include11 pieces of terminals arranged from right: HDATA (B), HCLK (B), DATAL(B), CLK (B), DATAB (B), RDY (B), GND (B), V33 (B), PGND (B), VBAT (B),and the leftmost LDET (B). Each body-side terminal is a conductive pin.The body-side terminals are forced with a spring or the like (notillustrated) in the −Z direction (FIG. 1). The −Z direction is adirection toward the interchangeable lens 3 attached to the camera andalso a direction of a subject.

The body-side mount 21 includes a through hole for a lock pin 42. Thethrough hole for the lock pin 42 is located to the upper right of thefourth body-side claw 29 d. In other words, the through hole for thelock pin 42 is located in the ring-shaped reference plane between anarea where the fourth body-side claw 29 d is present and an area wherethe first body-side claw 29 a is present in the opening in the body-sidemount 21. The lock pin 42 is forced with a spring or the like (notillustrated) in the −Z direction (FIG. 1).

FIG. 5B is a schematic drawing illustrating the camera body 2 in thestate that the body-side mount 21 has been removed as viewed from theside of the interchangeable lens 3. A first flat spring 41 a is providedin a position corresponding to the first body-side claw 29 a (behind thefirst body-side claw 29 a). Similarly, a second flat spring 41 b isprovided in a position corresponding to the second body-side claw 29 b(behind the second body-side claw 29 b), a third flat spring 41 c isprovided in a position corresponding to the third body-side claw 29 c(behind the third body-side claw 29 c), and a fourth flat spring 41 d isprovided in a position corresponding to the fourth body-side claw 29 d(behind the fourth body-side claw 29 d). In the following description,these four flat springs are collectively referred to as flat springs 41.The flat springs 41 press the lens-side claws described later in the +Zdirection (toward the camera body 2).

FIG. 6 schematically illustrates a mount of the interchangeable lens 3as viewed from the side of the camera body 2. The interchangeable lens 3includes the lens-side mount 31 and the lens-side terminal holding unit32 as described with reference to FIG. 1. The lens-side mount 31 has areference plane of a ring shape that has a constant width. Once theinterchangeable lens 3 is attached to the camera body 2, the ring-shapedreference plane of the lens-side mount 31 is in contact with thering-shaped reference plane of the body-side mount 21 described above.The lens-side mount 31 includes a cylindrical section extending in theoptical axis direction on its inner circumstance. Along the outercircumstance of the cylindrical section, the lens-side mount 31 includesa first lens-side claw 39 a, a second lens-side claw 39 b, a thirdlens-side claw 39 c, and a fourth lens-side claw 39 d that are spacedapart from each other. In the following description, these four clawsare collectively referred to as lens-side claws 39.

The lens-side claws 39 protrude from the outer circumstance of thecylindrical section of the lens-side mount 31 outward of the mount(radially from the optical axis O). As illustrated in FIG. 6, the firstlens-side claw 39 a is located at an upper left position, the secondlens-side claw 39 b is located at an upper right position, the thirdlens-side claw 39 c is located at a lower right position, and the fourthlens-side claw 39 d is located at a lower left position. Behind each ofthe lens-side claws 39 (on the side of the reference plane of thelens-side mount 31), there is a space where the corresponding one ofbody-side claws 29 enters once the interchangeable lens 3 is attached tothe camera body 2.

In the inside of an opening of the lens-side mount 31, the lens-sideterminal holding unit 32 is located. The lens-side terminal holding unit32 has an arc shape corresponding to the shape of the ring-shapedlens-side mount 31. Preferably, the lens-side terminal holding unit 32is located on an upper portion of the lens-side mount 31 along theopening in the lens-side mount 31, in the center of the upper portion asillustrated in FIG. 6. The lens-side terminal holding unit 32 includes aplurality of lens-side terminals as described above. The plurality oflens-side terminals are arranged in the lens-side terminal holding unit32 in arc shape in one line inside the lens-side mount 31. Asillustrated in FIG. 6, the plurality of lens-side terminals include 11pieces of terminals arranged from right: LDET (L), VBAT (L), PGND (L),V33 (L), GND (L), RDY (L), DATAB (L), CLK (L), DATAL (L), HCLK (L), andHDATA (L). The lens-side terminals are arranged such that a conductivecontact surface of each terminal is exposed in the +Z direction (FIG.1). The +Z direction is a direction in which light from a subjectpassing through the imaging optical system 36 travels toward the imagesensor 27.

The lens-side mount 31 includes a lock pin receiving section 43. Asillustrated in FIG. 6, the lock pin receiving section 43 is located tothe upper left of the fourth lens-side claw 39 d. In other words, thelock pin receiving section 43 is located between a portion correspondingto the first lens-side claw 39 a and a portion corresponding to thefourth lens-side claw 39 d in the lens-side mount 31. The lock pinreceiving section 43 is a groove accommodating the lock pin 42 once theinterchangeable lens 3 is attached to the camera body 2. The directionof the depth of the groove is provided along the −Z direction (FIG. 1).

Once the interchangeable lens 3 is attached to the camera body 2, theplurality of body-side terminals are physically in contact with theirrespective corresponding lens-side terminals. The contact electricallyconnects the plurality of body-side terminals with the plurality oflens-side terminals. In other words, the plurality of body-sideterminals and the plurality of lens-side terminals are in electricalcontinuity with each other.

Attachment of Interchangeable Lens

Description will now be made as to how the interchangeable lens 3 isattached to the camera body 2. To attach the interchangeable lens 3 tothe camera body 2, first the lend-side mount 31 is placed face to facewith the body-side mount 21, then the first lens-side claw 39 a isaligned with the first body-side through section 40 a, the secondlens-side claw 39 b is aligned with the second body-side through section40 b, the third lens-side claw 39 c is aligned with the third body-sidethrough section 40 c, and the fourth lens-side claw 39 d is aligned withthe fourth body-side through section 40 d. Then, the first lens-sideclaw 39 a is inserted into the first body-side through section 40 a, thesecond lens-side claw 39 b is inserted into the second body-side throughsection 40 b, the third lens-side claw 39 c is inserted into the thirdbody-side through section 40 c, and the fourth lens-side claw 39 d isinserted into the fourth body-side through section 40 d. At this time,the LDET (L) terminal is brought into contact with the CLK (B) terminal,the VBAT (L) terminal is brought into contact with the DATAL (B)terminal, the PGND (L) terminal is brought into contact with the HCLK(B) terminal, and the V33 (L) terminal is brought into contact with theHDATA (B) terminal.

From this state, the interchangeable lens 3 is rotated in an attachmentdirection 44 as illustrated in FIGS. 5A and 6. Consequently, the firstbody-side claw 29 a enters a space behind the first lens-side claw 39 a,the second body-side claw 29 b enters a space behind the secondlens-side claw 39 b, the third body-side claw 29 c enters a space behindthe third lens-side claw 39 c, and the fourth body-side claw 29 d entersa space behind the fourth lens-side claw 39 d. At this time, theplurality of lens-side terminals are brought into contact with theplurality of body-side terminals in order. Instead of theinterchangeable lens 3, the camera body 2 may be rotated in the reversedirection with respect to the attachment direction 44 illustrated inFIGS. 5A and 6.

While the lens-side claws 39 are inserted in their correspondingbody-side through sections 40 and the interchangeable lens 3 is rotatedin the attachment direction 44, for example, the LDET (L) terminal isbrought into contact with the CLK (B) terminal, the DATAB (B) terminal,the RDY (B) terminal, the GND (B) terminal, the V33 (B) terminal, thePGND (B) terminal, the VBAT (B) terminal and the LDET (B) terminal, inorder. For example, the VBAT (L) terminal is brought into contact withthe DATAL (B) terminal, the CLK (B) terminal, the DATAB (B) terminal,the RDY (B) terminal, the GND (B) terminal, the V33 (B) terminal, thePGND (B) terminal, and the VBAT (B) terminal, in order. For example, thePGND (L) terminal is brought into contact with the HCLK (B) terminal,the DATAL (B) terminal, the CLK (B) terminal, the DATAB (B) terminal,the RDY (B) terminal, the GND (B) terminal, the V33 (B) terminal, andthe PGND (B) terminal, in order. For example, the V33 (L) terminal isbrought into contact with the HDATA (B) terminal, the HCLK (B) terminal,the DATAL (B) terminal, the CLK (B) terminal, the DATAB (B) terminal,the RDY (B) terminal, the GND (B) terminal, and the V33 (B) terminal, inorder. For example, the GND (L) terminal is brought into contact withthe HDATA (B) terminal, the HCLK (B) terminal, the DATAL (B) terminal,the CLK (B) terminal, the DATAB (B) terminal, the RDY (B) terminal, andthe GND (B) terminal, in order.

For example, the RDY (L) terminal is brought into contact with the HDATA(B) terminal, the HCLK (B) terminal, the DATAL (B) terminal, the CLK (B)terminal, the DATAB (B) terminal, and the RDY (B) terminal, in order.For example, the DATAB (L) terminal is brought into contact with theHDATA (B) terminal, the HCLK (B) terminal, the DATAL (B) terminal, theCLK (B) terminal, and the DATAB (L) terminal, in order. For example, theCLK (L) terminal is brought into contact with the HDATA (B) terminal,the HCLK (B) terminal, the DATAL (B) terminal, and the CLK (B) terminal,in order. For example, the DATAL (L) terminal is brought into contactwith the HDATA (B) terminal, the HCLK (B) terminal, and the DATAL (B)terminal, in order. For example, the HCLK (L) terminal is brought intocontact with the HDATA (B) terminal and the HCLK (B) terminal, in order.

Upon rotating the interchangeable lens 3 by a predetermined angle withrespect to the camera body 2, an attachment completion position isreached. In the attachment completion position, the body-side claws 29and the lens-side claws 39 are placed face to face with each other inthe optical axis direction, and the lock pin 42 is pushed in the −Zdirection in FIG. 1 into the lock pin receiving section 43. Once thelock pin 42 enters the lock pin receiving section 43, theinterchangeable lens 3 cannot be rotated with respect to the camera body2 to remove the lens. In other words, once the body-side claws 29 andthe lens-side claws 39 reach a predetermined attachment completionposition, the relative position between the body-side mount 21 and thelens-side mount 31 is fixed. The lens-side claws 39 are pressed to thebody side (+Z direction in FIG. 1) by the flat springs 41. Thereby, eachof the plurality of lens-side terminals is in contact with andelectrically connected to each of their respective correspondingbody-side terminals.

In the following description, the state where the body-side claws 29 andthe lens-side claws 39 reach the attachment completion position isreferred to as an attachment completion state. During rotation from theposition where the lens-side claw 39 is inserted into the body-sidethrough section 40 to a position immediately before the attachmentcompletion position or during rotation from a position immediatelybefore the attachment completion position to the insertion position isreferred to as an attachment incompletion state.

During the attachment incompletion state, the signal level of the LDET(B) terminal is pulled up and at a high level. While it is detected thatthe signal level of the LDET (B) terminal is at a high level, thebody-side control unit 23 determines that the interchangeable lens 3 isnot attached. While the interchangeable lens 3 is not attached, thebody-side control unit 23 does not allow the power unit 26 to supplypower to the VBAT (B) terminal and the V33 (B) terminal.

In the attachment completion state, the signal level of the LDET (B)terminal is pulled down to a low level as described above (FIG. 2). Upondetection of the signal level of the LDET (B) terminal reaching a lowlevel, the body-side control unit 23 determines that the interchangeablelens 3 is attached. Also in the attachment completion state, the lockpin 42 enters the lock pin receiving section 43 and a switch 28 (FIG. 1)associated with the lock pin 42 is turned on. Upon detection of thesignal level of the LDET (B) terminal reaching a low level and theswitch 28 being turned on, the body-side control unit 23 causes thepower unit 26 to start supplying power to the V33 (B) terminal. It willbe noted that the camera body 2 is not necessarily provided with theswitch 28. In the case where the switch 28 is not provided, the powerunit 26 may be allowed to supply power to the V33 (B) terminal upondetection of the signal level of the LDET (B) terminal reaching a lowlevel.

Once the supply of power to the V33 (B) terminal is started, power issupplied to the lens-side control unit 33 of the interchangeable lens 3through the V33 (L) terminal and the lens-side control unit 33 startsoperation. The lens-side control unit 33, that has started operation,permits initial communication with the body-side control unit 23 bymeans of the command data communication. After the lens-side controlunit 33 permits initial communication, the body-side control unit 23starts the initial communication. The initial communication includes arequest for a power supply to the VBAT (L) terminal by the lens-sidecontrol unit 33. Once a signal requesting for a power supply to the VBAT(L) terminal is transmitted from the lens-side control unit 33 to thebody-side control unit 23, the body-side control unit 23 supplies powerto the VBAT (B) terminal and an initialization process between thecamera body 2 and the interchangeable lens 3 is executed. In theinitialization process, information required for various operations ofthe camera system 1, such as imaging operation and focus adjustingoperation, is exchanged between the camera body 2 and theinterchangeable lens 3, a lens position of the interchangeable lens istransferred to a reference position, and so on.

In the attachment completion state, upon an unlocking button (notillustrated) of the camera body being pressed by a user, the lock pin 42retracts from the lock pin receiving section 43. This allows therelative position between the body-side mount 21 and the lens-side mount31 to be changed. Upon an unlocking button (not illustrated) beingpressed by a user to turn off the switch 28 associated with theunlocking button, the body-side control unit 23 causes the power unit 26to stop supplying power to the VBAT (B) terminal and the V33 (B)terminal. From that state, while the interchangeable lens 3 is rotatedin a direction opposite to the attachment direction 44 as illustrated inFIGS. 5A and 6, the plurality of lens-side terminals are brought intocontact with the plurality of body-side terminals in the reverse orderto that as described above.

The supply of power may not be stopped in response to the operation ofthe unlocking button. In this case, upon detection of the signal levelof the LDET (B) terminal changing from the low level to the high levelbecause the LDET (L) terminal is separated from the LDET (B) terminaldue to the rotation of the interchangeable lens 3 in the directionopposite to the attachment direction 44, the body-side control unit 23causes the power unit 26 to stop supplying power to the VBAT (B)terminal and the V33 (B) terminal. In this way, the number of componentsof the camera system 1 can be reduced. It will be noted that, thebody-side control unit 23 may cause the power unit 26 to stop supplyingpower to the VBAT (B) terminal and the V33 (B) terminal, upon detectionof both the unlocking button being pressed and the signal level of theLDET (B) terminal changing from the low level to the high level.Alternatively, the body-side control unit 23 may cause the power unit 26to stop supplying power to the VBAT (B) terminal and the V33 (B)terminal, upon detection of either one of the unlocking button beingpressed or the signal level of the LDET (B) terminal changing from thelow level to the high level.

As described above, during attachment and removal of the interchangeablelens to and from the camera body (the attachment incompletion state),the lens-side terminals are brought into contact with other body-sideterminals than those intended to match upon completion of attachment. Itis preferable that the arrangement of lens-side and body-side terminalsshould cause less trouble that may occur due to the contact duringattachment and removal.

Terminal Arrangement with Noises Taken into Consideration

In the present embodiment, among the plurality of body-side terminals,the LDET (B) terminal is positioned at the headmost end in theattachment direction (the arrow 44 in FIG. 5A) of the lens. In otherwords, the location of the LDET (B) terminal is the leftmost side of thebody-side terminal group in FIG. 5A as described above. Similarly, amongthe plurality of lens-side terminals, the LDET (L) terminal ispositioned at the headmost end in the attachment direction (the arrow 44in FIG. 6) of the lens. In other words, the location of the LDET (L)terminal is the rightmost side of the lens-side terminal group in FIG. 6as described above. Consequently, the LDET (B) terminal is not broughtinto contact with other lens-side terminals than the LDET (L) terminaluntil the attachment of the interchangeable lens is completed. As aresult, the signal level of the LDET (B) terminal is not accidentally bebrought to the low level in the process of attachment of theinterchangeable lens, and thus an erroneous recognition of the lensattachment can be avoided.

In the present embodiment, the VBAT (B) terminal is positioned next tothe LDET (B) terminal, that is, at the second place from the headmostend in the attachment direction. The VBAT (L) terminal is positionednext to the LDET (L) terminal, that is, at the second place from theheadmost end in the attachment direction. The purpose of sucharrangement is to reduce the number of lens-side terminals that the VBAT(B) terminal on the camera body side contacts in the process ofattachment of the interchangeable lens. The voltage applied to the VBAT(B) terminal is higher than the voltage applied to any other terminals,and if the VBAT (B) terminal is brought into contact with any otherterminal than the VBAT (L) terminal in such a situation that a highvoltage is applied to the VBAT (B) terminal due to, for example, afailure of the camera system 1, the high voltage may place an unexpectedload on electric circuits in the interchangeable lens. In the presentembodiment, the VBAT (B) terminal is located next to the LDET (B)terminal, only the LDET (L) terminal among the plurality of thelens-side terminals is brought into contact with the VBAT (B) terminalduring attachment of the interchangeable lens 3. As illustrated in FIG.2, the LDET (L) terminal is grounded through the resistor R3, and evenif a high voltage is applied from the VBAT (B) terminal, the camerasystem 1 may not be affected.

In the present embodiment, the PGND (B) terminal is positioned next tothe VBAT (B) terminal, that is, at the third place from the headmost endin the attachment direction. The PGND (L) terminal is positioned next tothe VBAT (L) terminal, that is, at the third place from the headmost endin the attachment direction. The capacitor C1 connected to the VBAT (L)terminal is supplied with and charged by a high voltage from the VBAT(B) terminal. While the interchangeable lens 3 is rotated in a removaldirection, the VBAT (L) terminal is first brought into contact with thePGND (B) terminal. The charge stored on the capacitor C1 is rapidlydischarged through the PGND (B) terminal, which is a ground terminal,and other circuits in the camera system 1 may not be affected.

In the present embodiment, the V33 (B) terminal is positioned next tothe PGND (B) terminal, that is, at the fourth place from the headmostend in the attachment direction, and the GND (B) terminal is positionednext to the V33 (B) terminal, that is, at the fifth place from theheadmost end. The V33 (L) terminal is positioned next to the PGND (L)terminal, that is, at the fourth place from the headmost end in theattachment direction, and the GND (L) terminal is positioned next to theV33 (L) terminal, that is, at the fifth place from the headmost end. Thecapacitor C2 connected to the V33 (L) terminal is supplied with andcharged by a voltage from the V33 (B) terminal. While theinterchangeable lens 3 is rotated in the removal direction, the V33 (L)terminal is first brought into contact with the GND (B) terminal. Thecharge stored on the capacitor C2 is rapidly discharged through the GND(B) terminal, which is a ground terminal, and other circuits in thecamera system 1 may not be affected.

The RDY (B) terminal is positioned next to the GND (B) terminal, thatis, at the sixth place from the headmost end, the DATAB (B) terminal ispositioned next to the RDY (B) terminal, that is, at the seventh placefrom the headmost end, the CLK (B) terminal is positioned next to theDATAB (B) terminal, that is, at the eighth place from the headmost end,the DATAL (B) terminal is positioned next to the CLK (B) terminal, thatis, at the ninth place from the headmost end, the HCLK (B) terminal ispositioned next to the DATAL (B) terminal, that is, at the tenth placefrom the headmost end, and the HDATA (B) terminal is positioned next tothe HCLK (B) terminal, that is, at the last end.

The RDY (L) terminal is positioned next to the GND (L) terminal, thatis, at the sixth place from the headmost end, the DATAB (L) terminal ispositioned next to the RDY (L) terminal, that is, at the seventh placefrom the headmost end, the CLK (L) terminal is positioned next to theDATAB (L) terminal, that is, at the eighth place from the headmost end,the DATAL (L) terminal is positioned next to the CLK (L) terminal, thatis, at the ninth place from the headmost end, the HCLK (L) terminal ispositioned next to the DATAL (L) terminal, that is, at the tenth placefrom the headmost end, and the HDATA (L) terminal is positioned next tothe HCLK (L) terminal, that is, at the last end.

Next, description will be made as to an effect of noise caused bycommunication lines formed between the body-side terminals and thelens-side terminals. In the hot-line communication, information istransmitted to the body one-sidedly after the communication is startedand the communication is performed highly frequently (repeated in ahighly short cycle). In the hot-line communication, a clock signal istransmitted from the HCLK (L) terminal to the HCLK (B) terminal. Theclock signal is a cyclic signal of high and low levels in a highly shortcycle, and thus may be a major cause of noise for other signals.Further, the clock signal transmitted from the HCLK (L) terminal to theHCLK (B) terminal is a signal output from the interchangeable lens 3, sothat even if the clock signal is accidentally affected by a noise, thenoise cannot be recognized on the side of the camera body 2.Accordingly, a signal flowing through the HCLK terminals may be a causeof noise for the camera body 2 and may be a cause of a fault operationof the camera system 1. Examples of such a fault operation includeerroneous detection of attachment of the interchangeable lens andmisjudging whether or not the command communication is allowed. In thepresent embodiment, the HCLK terminal is positioned away from the VBATterminal to which a high voltage is applied. In addition, the HCLKterminal is positioned away from the RDY terminal such that the HCLKterminal is not adjacent to the RDY terminal that is used to indicatewhether or not the command communication is allowed.

The HDATA terminal and the DATAL terminal are arranged on opposite sidesof the HCLK terminal. With this arrangement, effects of noises from theHCLK terminal on other terminals than the HDATA terminal and DATALterminal can be suppressed.

The command data communication is a communication for bi-directionallytransmitting and receiving information between the body and theinterchangeable lens, as described above. In the command datacommunication, a clock signal is transmitted from the CLK (B) terminalto the CLK (L) terminal. The clock signal transmitted through the CLKterminals may also be a cause of noise for the same reason as describedabove. In the present embodiment, therefore, the CLK terminal ispositioned away from the VBAT terminal to which a high voltage isapplied. In addition, the CLK terminal is positioned away from the RDYterminal such that the HCLK terminal is not adjacent to the RDY terminalthat are used to indicate whether or not the command communication isallowed. Further, if the HCLK terminal and the CLK terminal are adjacentto each other, one clock signal may affect the other clock signal,providing a cause of noise. In the present embodiment, the DATALterminal is positioned between the CLK terminal and the HCLK terminal.In addition, the DATAB terminal is positioned between the CLK terminaland the RDY terminal. In other words, the DATAL terminal and DATABterminal are arranged on opposite sides of the CLK terminal.Consequently, effects of noises originating from the CLK terminals onthe camera system can be suppressed.

As also described above, it is necessary to discriminate the level ofthe RDY terminals in order to perform the command data communication.This means that a noise has a major effect on imaging operation becausethe signal level of the RDY terminals are indicative of whether or notthe command data can be communicated. Consider here the case where thebody-side control unit 23 erroneously recognizes due to a noise thatcommand data can be communicated despite the situation where the commanddata cannot be communicated. In this case, although the lens-sidecontrol unit 33 cannot receive command data, the body-side control unit23 transits the command data and the body-side control unit 23erroneously recognizes that control will be made on the interchangeablelens according to the command data. However, since the lens-side controlunit 33 cannot accept the command data, the control according to sucherroneously transmitted command data is no longer be made. As a result,the operation of the camera system 1 may be disrupted. Accordingly, itis necessary to prevent noises from affecting signals on the RDYterminals. To prevent noises from affecting signals on the RDYterminals, it is desirable that terminals through which relativelystable signals, that is, those signals that have less variation in thesignal level per unit time are positioned on opposite sides of the RDYterminal. In the present embodiment, the GND terminal and the DATABterminal are arranged on opposite sides of the RDY terminal. The GNDterminals, which are at ground potential, are stable and the DATABterminals are also terminals through which more stable signals flow thanthe CLK terminals and the HCLK terminals. Consequently, effects ofnoises affecting the RDY terminals can be suppressed.

Next, power supplied from the VBAT (B) terminal to the VBAT (L) terminalis used to drive the actuator (for example, stepping motor) of thedriving unit 37 of the interchangeable lens 3. Accordingly, currentflowing through the VBAT terminals largely vary between a period inwhich the actuator is driven and a period in which the actuator is notdriven. Such variation in the current may be a cause of noise on signalsflowing through other terminals. In the present embodiment: the VBATterminal is positioned away from the RDY terminal, the DATAB terminal,the CLK terminal, and the DATAL terminal, which are used for the commanddata communication, and the HCLK terminal and the HDATA terminal, whichare used for the hot-line communication. Further, the GND terminal, theV33 terminal, and the PGND terminal are positioned between the VBATterminal and the terminal used for both modes of the communication.Consequently, effects of noises caused by the variation in currentflowing through the VBAT terminals on the data communication can besuppressed.

The terminal arrangement with noises taken into consideration asdescribed above will now be summarized.

The RDY terminal is positioned away from both the VBAT terminal and theHCLK terminal, which each may be a cause of noise, such that the RDYterminal is not adjacent to both the VBAT terminal and the HCLKterminal. Consequently, effects of noises on the RDY terminals that areused to indicate whether or not the command communication is allowed canbe suppressed.

The HCLK terminal that may be a cause of noise is positioned between theHDATA terminal and the DATAL terminal, and the CLK terminal ispositioned between the DATAL terminal and the DATAB terminal. In otherwords, the HDATA terminal, the HCLK terminal, the DATAL terminal, theCLK terminal, and the DATAB terminal are arranged in order from the lastend in the attachment direction. Consequently, effects of noises causedby a clock signal into the RDY and the like terminals can be suppressed.

Further, in consideration of effects of noises, terminals for powersupply are positioned away from terminals used for communication acrossthe RDY terminals. Specifically, with the RDY terminal in between, onthe head end side from the RDY terminal, terminals for power supply: theVBAT terminal, the PGND terminal, the V33 terminal, and the GND terminalare arranged in order from the head end side, and on the last end sidefrom the RDY terminal, terminals used for communication: the DATABterminal, the CLK terminal, the DATAL terminal, the HCLK terminal, andthe HDATA terminal are arranged in order from the head end side.Consequently, effects of noises from the terminals for power supply suchas the VBAT terminals and the terminals used for communication such asthe HCLK or CLK terminals on the RDY terminals can be suppressed.

As for the HCLK terminals through which a clock signal used for thehot-line communication and the CLK terminals through which a clocksignal used for the command data communication, the HCLK terminal ispositioned farther away from the VBAT terminal than the CLK terminal.The reason is as follows. The clock signal transmitted to theinterchangeable lens 3 through the CLK terminals are output by thebody-side control unit 23 through the body-side communication unit 24.However, any noise affecting the clock signal transmitted to the camerabody through the HCLK terminals from the interchangeable lens via thelens-side communication unit 34 may be a cause of erroneous recognitionby the body-side control unit 23. This means that a noise affecting theclock signal on the HCLK terminals has a greater effect on the camerasystem 1.

As for the HCLK terminals and the GND terminals, the HCLK terminal ispositioned farther away from the VBAT terminal than the GND terminal. Inaddition, the PGND terminal is positioned between the GND terminal andthe VBAT terminal. Consequently, the HCLK terminals through which theclock signal used for the hot-line communication is transmitted can beshielded from any noise originating from the VBAT terminals.

As for the CLK terminals and the GND terminals, the CLK terminal ispositioned farther away from the VBAT terminal than the GND terminal. Inaddition, the PGND terminal is positioned between the GND terminal andthe VBAT terminal. In this way, the CLK terminals through which theclock signal used for the command data communication is transmitted canbe shielded from any noise originating from the VBAT terminals.

Terminal Arrangement with Wear Taken into Consideration

Description will now be made as to contacts between terminals duringattachment and removal of the interchangeable lens 3 to and from thecamera body 2.

During attachment of the interchangeable lens 3 to the camera body 2,the body-side terminals are brought into contact with the lens-sideterminals in succession. The same applies to during removal of theinterchangeable lens 3 from the camera body 2. In other words, thebody-side terminals, which are pins protruding from the body-sideterminal holding unit 22, are rubbed against the lens-side terminals,which are exposed conductive contact surfaces, in succession. Since morethan one interchangeable lens may be attached and removed to and fromone camera body, the body-side terminals are more prone to wear than thelens-side terminals. In particular, the body-side terminals locatednearer to the last end in the attachment direction of theinterchangeable lens 3 are rubbed against more lens-side terminals andmore subjected to wear. Consequently, the body terminals located nearerto the last end are more subjected to wear on pin tips than thebody-side terminals located nearer to the head end. Wear on thebody-side terminals may have an effect on contactability with thelens-side terminals, and thus may cause unstable data communication.

In the present embodiment, the LDET (B) terminal is positioned at theheadmost end in the attachment direction, and thus the LDET (B) terminalmay be subjected to the least wear. In this way, the LDET (B) terminaland the LDET (L) terminal make a good contact with each other, resultingin less possibility of erroneous detection of attachment or removal ofthe interchangeable lens 3.

As described above, in the present embodiment, the CLK (B) terminal andthe HCLK (B) terminal are positioned away from the VBAT (B) terminal inorder to suppress effects of noises on communication. In other words,the VBAT (B) terminal is positioned at the second place from the headend in the attachment direction, and the CLK (B) terminal and the HCLK(B) terminal are positioned in the last end side away from the VBAT (B)terminal. Accordingly, the CLK (B) terminal and the HCLK (B) terminalare more subjected to wear than the LDET (B) terminal and the VBAT (B)terminal. In the present embodiment, the CLK (B) terminal and the HCLK(B) terminal are positioned immediately close to the first body-sideclaw 29 a. Specifically, the CLK (B) terminal and the HCLK (B) terminalare positioned nearer to the inner circumferential edge of the firstbody-side claw 29 a than the VBAT (B) terminal. In other words, thedistance between the CLK (B) terminal and the inner circumferential edgeof the first body-side claw 29 a is shorter than the distance betweenthe VBAT (B) terminal and the inner circumferential edge of the firstbody-side claw 29 a, and the distance between the HCLK (B) terminal andthe inner circumferential edge of the first body-side claw 29 a isshorter than the distance between the VBAT (B) terminal and the innercircumferential edge of the first body-side claw 29 a. As describedabove, the first flat spring 41 a is provided behind the first body-sideclaw 29 a, and the first lens-side claw 39 a is pressed in the +Zdirection (FIG. 1) by the first flat spring 41 a. From the first flatspring 41 a viewpoint, both the distance between the CLK (B) terminaland the first flat spring 41 a and the distance between the HCLK (B)terminal and the first flat spring 41 a are shorter than the distancebetween the VBAT (B) terminal and the first flat spring 41 a. The LDET(B) terminal is similar to the VBAT (B) terminal; both the distancebetween the CLK (B) terminal and the first flat spring 41 a and thedistance between the HCLK (B) terminal and the first flat spring 41 aare shorter than the distance between the LDET (B) terminal and thefirst flat spring 41 a. Consequently, both the CLK (B) terminal and theHCLK (B) terminal are pressed against the lens-side terminals moreforcefully than the VBAT (B) terminal and the LDET (B) terminal arepressed against the lens-side terminals.

On the lens side, the CLK (L) terminal and the HCLK (L) terminal arepositioned nearer to the inner circumferential edge of the firstlens-side claw 39 a than the VBAT (L) terminal. In other words, thedistance between the CLK (L) terminal and the inner circumferential edgeof the first lens-side claw 39 a is shorter than the distance betweenthe VBAT (L) terminal and the inner circumferential edge of the firstlens-side claw 39 a, and the distance between the HCLK (L) terminal andthe inner circumferential edge of the first lens-side claw 39 a isshorter than the distance between the VBAT (L) terminal and the innercircumferential edge of the first lens-side claw 39 a. Accordingly, inthe attachment completion state, the CLK (L) and HCLK (L) terminalslocated close to the first lens-side claw 39 a are pressed against theircorresponding body-side terminals by the first flat spring 41 a. TheLDET (L) terminal is similar to the VBAT (L) terminal; in the attachmentcompletion state, both the distance between the CLK (L) terminal and thefirst flat spring 41 a and the distance between the HCLK (L) terminaland the first flat spring 41 a are shorter than the distance between theLDET (L) terminal and the first flat spring 41 a. Consequently, in theattachment completion state, a stronger pressing force against thebody-side terminals acts on the CLK (L) terminal and HCLK (L) terminalthan the LDET (L) terminal are pressed against the body-side terminals.Consequently, even if the CLK (B) terminal or the HCLK (B) terminal issubjected to wear, good contact can be maintained, resulting in a stableclock signal and stable data communication. In addition, for example,even in case of impact on the camera body 2 or the interchangeable lens3 while the attachment completion state is maintained, contact betweenthe CLK (B) terminal and the CLK (L) terminal and contact between theHCLK (B) terminal and the HCLK (L) terminal can be maintained.

Even in the case where the first lens-side claw 39 a has a partialcutout, a combination of a protruding portion and a cut-out portionlocated in an area where they face the first body-side claw 29 a shallserve as the first lens-side claw. As for how the cutout is made, thelens-side claw may be circumferentially separated into two or moreparts; a part of the lens-side claw may be cut out; or at least a partof the lens-side claw may be cut out such that a radial direction lengthis shortened. A circumferential length of the lens-side claw may bealtered to the extent that the corresponding body-side through sectioncan pass therethrough. The same applies to the second lens-side claw 39b, the third lens-side claw 39 c, and fourth lens-side claw 39 d. Aradial thickness of the cylindrical section may be altered as necessaryand the shape may have at least a partial inward protrusion as comparedto the cylindrical section of the present embodiment.

As described above, the CLK (B) terminal and the HCLK (B) terminal aremore subjected to wear than the LDET (B) terminal and the VBAT (B)terminal. In the present embodiment, the CLK (B) terminal and the HCLK(B) terminal are both positioned immediately close to the firstbody-side claw 29 a. Specifically, the CLK (B) terminal and the HCLK (B)terminal are positioned nearer to the inner circumferential edge of thefirst body-side claw 29 a than the LDET (B) terminal and the VBAT (B)terminal. In other words, the distance between the CLK (B) terminal andthe inner circumferential edge of the first body-side claw 29 a isshorter than the distance between the LDET (B) terminal and the innercircumferential edge of the first body-side claw 29 a or the distancebetween the VBAT (B) terminal and the inner circumferential edge of thefirst body-side claw 29 a, and the distance between the HCLK (B)terminal and the inner circumferential edge of the first body-side claw29 a is shorter than the distance between the LDET (B) terminal and theinner circumferential edge of the first body-side claw 29 a or thedistance between the VBAT (B) terminal and the inner circumferentialedge of the first body-side claw 29 a. As described above, the firstflat spring 41 a is provided behind the first body-side claw 29 a, andthe first lens-side claw 39 a is pressed in the +Z direction (FIG. 1) bythe first flat spring 41 a. From the first flat spring 41 a viewpoint,both the distance between the CLK (B) terminal and the first flat spring41 a and the distance between the HCLK (B) terminal and the first flatspring 41 a are shorter than the distance between the LDET (B) terminalor the VBAT (B) terminal and the first flat spring 41 a.

On the lens side, the CLK (L) terminal and the HCLK (L) terminal arepositioned nearer to the inner circumferential edge of the firstlens-side claw 39 a than the LDET (L) terminal and the VBAT (L)terminal. In other words, the distance between the CLK (L) terminal andthe inner circumferential edge of the first lens-side claw 39 a isshorter than the distance between the LDET (L) terminal and the innercircumferential edge of the first lens-side claw 39 a or the distancebetween the VBAT (L) terminal and the inner circumferential edge of thefirst lens-side claw 39 a, and the distance between the HCLK (L)terminal and the inner circumferential edge of the first lens-side claw39 a is shorter than the distance between the LDET (L) terminal theinner circumferential edge of the first lens-side claw 39 a or thedistance between the VBAT (L) terminal and the inner circumferentialedge of the first lens-side claw 39 a. Accordingly, the CLK (L) terminaland the HCLK (L) terminal located close to the first lens-side claw 39 aare pressed against their corresponding body-side terminals by the firstflat spring 41 a. Consequently, both the CLK (B) terminal and the HCLK(B) terminal are pressed against the lens-side terminals more forcefullythan the LDET (B) terminal or the VBAT (B) terminal. Consequently, evenif the CLK (B) terminal or the HCLK (B) terminal is subjected to wear,good contact can be maintained, resulting in stable data communication.In addition, for example, even in case of impact on the camera body 2 orthe interchangeable lens 3 while the attachment completion state ismaintained, contact between the CLK (B) terminal or the HCLK (B)terminal and the respective corresponding lens-side terminal can bemaintained.

In the present embodiment, the CLK (B) terminal and the HCLK (B)terminal are also near the fourth body-side claw 29 d. Specifically,both the CLK (B) terminal and the HCLK (B) terminal are positionednearer to the fourth body-side claw 29 d than the VBAT (B) terminal orthe LDET (B) terminal. In other words, the distance between the CLK (B)terminal and the fourth body-side claw 29 d is shorter than the distancebetween the VBAT (B) terminal and the fourth body-side claw 29 d or thedistance between the LDET (B) terminal and the fourth body-side claw 29d, and the distance between the HCLK (B) terminal and the fourthbody-side claw 29 d is shorter than the distance between the VBAT (B)terminal and the fourth body-side claw 29 d or the distance between theLDET (B) terminal and the fourth body-side claw 29 d. As describedabove, the fourth flat spring 41 d is provided behind the fourthbody-side claw 29 d, and the fourth lens-side claw 39 d is pressed inthe +Z direction (FIG. 1) by the fourth flat spring 41 d. Accordingly,each the CLK (B) terminal and the HCLK (B) terminal located near thefourth lens-side claw 39 d are respectively pressed against thecorresponding lens-side terminal stronger and in a more stable mannerthan the VBAT (B) terminal or the LDET (B) terminal by the fourth flatspring 41 d.

The distance between the CLK (B) terminal and the first body-side claw29 a (the same applies to the fourth lens-side claw 39 d that is omittedin the following description) as described above refers to a distance ina straight line between one end of the first body-side claw 29 a and theCLK (B) terminal, and may be defined as a distance in a straight linebetween the other end of the first body-side claw 29 a and the CLK (B)terminal. Alternatively, the distance between the CLK (B) terminal andthe first body-side claw 29 a as described above may be defined as adistance in a straight line between a middle position of the firstbody-side claw 29 a in the circumferential direction of the body-sidemount 21 and the CLK (B) terminal. Each of the distances between otherbody-side terminals such as the HCLK (B) terminal, the VBAT (B)terminal, and the LDET (B) terminal and the first body-side claw 29 aare also a distances in a straight line. The distance between the firstflat spring 41 a (or the fourth flat spring 41 d) and each of body-sideterminals are also a distance in a straight line.

The distance between the CLK (B) terminal and the first body-side claw29 a (the same applies to the fourth body-side claw 29 d that is omittedin the following description) as described above may be defined as adistance on the arc between one end of the first body-side claw 29 a inthe circumferential direction of the body-side mount 21 and the CLK (B)terminal, or may be defined as a distance on the arc between the otherend of the first body-side claw 29 a and the CLK (B) terminal.Alternatively, the distance between the CLK (B) terminal and the firstbody-side claw 29 a as described above may be defined as a distance onthe arc between a middle position of the first body-side claw 29 a inthe circumferential direction of the body-side mount 21 and the CLK (B)terminal. The distances between other body-side terminals such as theHCLK (B) terminal, the VBAT (B) terminal, and the LDET (B) terminal andthe first body-side claw 29 a may be also a distances on the arc. Thedistances between the first flat spring 41 a (or the fourth flat spring41 d) and each of body-side terminals may be also a distances on thearc.

Although description has been made as to the camera body 2, the sameapplies to the interchangeable lens 3. In the present embodiment, theCLK (L) terminal and the HCLK (L) terminal are both positionedimmediately close to the first lens-side claw 39 a. Specifically, boththe CLK (L) terminal and the HCLK (L) terminal are positioned nearer tothe first lens-side claw 39 a than the VBAT (L) terminal or the LDET (L)terminal. In other words, the distance between the CLK (L) terminal andthe first lens-side claw 39 a is shorter than the distance between theVBAT (L) terminal or the distance between the LDET (L) terminal and thefirst lens-side claw 39 a, and the distance between the HCLK (L)terminal and the first lens-side claw 39 a is shorter than the distancebetween the VBAT (L) terminal and the first lens-side claw 39 a or thedistance between the LDET (L) terminal and the first lens-side claw 39a. The first lens-side claw 39 a is pressed in the +Z direction (FIG. 1)by the first flat spring 41 a on the body side. Accordingly, similarlyto those described above, each the CLK (L) terminal and the HCLK (L)terminal located near the first lens-side claw 39 a are pressed againstthe corresponding body-side terminal more forcefully than the VBAT (L)terminal or the LDET (L) terminal by the first flat spring 41 a.

In the present embodiment, as illustrated in FIG. 5A, the CLK (B)terminal and the HCLK (B) terminal are arranged inside a sector (in therange of the angle of 50 degrees) formed by the center of the opening ofthe mount 21 (i.e. the position of the optical axis O of theinterchangeable lens 3) and the arc-like first body-side claw 29 a.Alternatively, the CLK (B) terminal and the HCLK (B) terminal arearranged inside a triangular area formed by the center of the opening ofthe mount 21 (i.e. the position of the optical axis O of theinterchangeable lens 3) and the both ends of the first body-side claw 29a on the inner circumferential side. Accordingly, the first body-sideclaw 29 a is not present on an extension of a dashed line 51 connectingthe center of the opening of the mount 21 with the LDET (B) terminal,but the first body-side claw 29 a is present on an extension of a dashedline 52 connecting the center of the opening of the mount 21 with theHCLK (B) terminal, and the first body-side claw 29 a is also present onan extension of a dashed line 53 connecting the center of the opening ofthe mount 21 with the CLK (B) terminal. Consequently, in the attachmentcompletion state, the CLK (B) terminal and the HCLK (B) terminal arepressed against the corresponding lens-side terminals more forcefullythan the LDET (B) terminal.

As illustrated in FIG. 6, the CLK (L) terminal and the HCLK (L) terminalare arranged inside a sector (in the range of the angle of 60 degrees)formed by the center of the opening of the mount 31 (i.e. the positionof the optical axis O of the interchangeable lens 3) and the arc-likefirst lens-side claw 39 a. Alternatively, the CLK (L) terminal and theHCLK (L) terminal are arranged inside a triangular area formed by thecenter of the opening of the mount 31 (i.e. the position of the opticalaxis O of the interchangeable lens 3) and the both ends of the firstlens-side claw 39 a on the outer circumferential side. Accordingly, thefirst lens-side claw 39 a is not present on an extension of a dashedline 61 connecting the center of the opening of the mount 31 with theLDET (L) terminal, but the first lens-side claw 39 a is present on anextension of a dashed line 62 connecting the center of the opening ofthe mount 31 with the HCLK (L) terminal, and the first lens-side claw 39a is also present on an extension of a dashed line 63 connecting thecenter of the opening of the mount 31 with the CLK (L) terminal.Consequently, in the attachment completion state, the CLK (L) terminaland the HCLK (L) terminal are in contact with the correspondingbody-side terminals more stably than the LDET (L) terminal. In otherwords, a stronger pressing force against the body-side terminals acts onthe CLK (L) terminal and the HCLK (L) terminal than the LDET (L)terminal. As a result, even if the tip of the CLK (B) terminal or theHCLK (B) terminal is subjected to wear, the clock signal can stably becommunicated between the camera body 2 and the interchangeable lens 3.

It may be possible to provide the following variations, and may also bepossible to combine one or more variations with the present embodimentdescribed above.

Variation 1

Any terminal used for the command data communication or the hot-linecommunication may also be provided with a function to transmit apower-on signal from the interchangeable lens 3 to the camera body 2.For example, the interchangeable lens 3 may have a power switchfunction. While the interchangeable lens 3 is in the attachmentcompletion state and the camera system 1 is in a powered-off state, thepower unit 26 supplies power to the lens-side control unit 33 of theinterchangeable lens 3 through the V33 (B) terminal. Upon operation ofthe power switch of the interchangeable lens 3, for example, thelens-side control unit 33 outputs the power-on signal to the RDY (L)terminal via the lens-side communication unit 34. Upon detection of thepower-on signal through the RDY (B) terminal via the body-sidecommunication unit 24, the body-side control unit 23 makes the camerasystem 1 transition from the powered-off state to a powered-on statesimilarly to the case where a power switch (not illustrated) on thecamera body 2 is operated.

Variation 2

In the embodiment, the DATAB (B) terminal is positioned on the head endside from the CLK (B) terminal in the attachment direction and the DATAL(B) terminal is positioned on the last end side; however, the positionsof the DATAB (B) and DATAL (B) terminals may be exchanged. In otherwords, from the head end side in the attachment direction, the DATAL (B)terminal, the CLK (B) terminal, and the DATAB (B) terminal may bearranged in order.

It will be noted that, in the embodiment described above, althoughdescription has been made with reference to an interchangeable lens fora camera as an example for an accessory, the accessory is not limited tothe interchangeable lens. For example, the accessory may include onethat is attached between the camera body and the interchangeable lens tochange the focal length of the interchangeable lens, such as a teleconverter, a wide converter, or a close up ring. Alternatively, theembodiment may be applicable to a mount adapter or the like forattaching an accessory including the interchangeable lens of a differentmount standard to the above-described camera body of a certain mountstandard. In other words, the embodiment may be applicable to anyaccessory as long as it is attached to a mount of a camera body to use.In these cases, the lens-side terminal group, the lens-side claws 39,and the lens-side communication unit 34 respectively correspond toaccessary-side terminal group, accessary-side protruding portions, andan accessary-side communication unit of the accessory, and so on.

In the embodiment described above, although description has been made asto an accessory that can be removably attached to a camera body, thecamera body described above may be a mount adapter for attaching aninterchangeable lens of the above-described mount standard to a camerabody that has a different mount standard from the above, or theembodiment may be configured to make the above-described accessoryattachable to the mount adapter.

It may be acceptable for the accessary according to the presentinvention to be configured in the following manner.

(1) The camera body includes a first camera-side data terminal thatoutputs a first data signal; the accessory further includes a seventhterminal that is brought into contact with the first camera-side dataterminal, wherein the seventh terminal is positioned between the secondterminal and the eighth terminal.(2) The camera body includes a second camera-side power supply terminalthat outputs second power, and a second camera-side ground terminalcorresponding to the second power; the accessory further includes afourth terminal that is brought into contact with the second camera-sidepower supply terminal, wherein the fourth terminal is positioned betweenthe second terminal and the eighth terminal.(3) The accessory further includes a control unit that controls drivingof at least one of a plurality of lenses and communication with thecamera body, wherein the second power is power supplied to the controlunit.(4) A second terminal is a terminal to which first power supplied fromthe camera body is input; a fifth terminal is a terminal to which asecond ground potential with respect to second power supplied from thecamera body is input; an eighth terminal is a terminal to which a firstclock signal from the camera body is input; and a tenth terminal is aterminal that outputs a second clock signal to the camera body, andwherein: a distance between the tenth terminal and the second terminalis longer than a distance between the eighth terminal and the secondterminal; and a distance between the eighth terminal and the secondterminal is longer than a distance between the fifth terminal and thesecond terminal.(5) A ninth terminal outputs a third data signal to the camera body,wherein the ninth terminal is positioned between the eighth terminal andthe tenth terminal.(6) A seventh terminal is a terminal to which a first data signal fromthe camera body is input, and wherein the seventh terminal is positionedbetween the second terminal and the eighth terminal.(7) The eighth terminal is positioned between the seventh terminal andthe ninth terminal.(8) A fourth terminal is a terminal to which second power supplied fromthe camera body is input, and wherein the fourth terminal is positionedbetween the second terminal and the eighth terminal.(9) The communication is command communication in which a first datasignal from the camera body is input to the seventh terminal using thefirst clock signal, and a third data signal is output from the ninthterminal to the camera body.(10) A third terminal is brought into contact with the first camera-sideground terminal, and wherein the third terminal is positioned betweenthe second terminal and the fifth terminal.(11) The camera body includes a third camera-side data terminal to whicha third data signal is input; and the accessory further includes a ninthterminal that is brought into contact with the third camera-side dataterminal, wherein the ninth terminal is positioned between the fifthterminal and the tenth terminal.(12) The camera body includes a first camera-side data terminal thatoutputs a first data signal; and the accessory further includes aseventh terminal that is brought into contact with the first camera-sidedata terminal, wherein the seventh terminal is positioned between thefifth terminal and the tenth terminal.(13) A third terminal is brought into contact with the first camera-sideground terminal, wherein the third terminal is positioned between thesecond terminal and the fifth terminal.(14) The seventh terminal is positioned between the fifth terminal andthe eighth terminal.(15) A fifth terminal is brought into contact with the secondcamera-side ground terminal, wherein the fifth terminal is positionedbetween the third terminal and the tenth terminal.(16) The accessory further includes a seventh terminal that is broughtinto contact with the first camera-side data terminal, wherein theseventh terminal is positioned between the third terminal and the tenthterminal.(17) An accessory that can be attached to a camera body, the camera bodyincluding a first camera-side clock terminal that outputs a first clocksignal, a first camera-side power supply terminal that outputs firstpower, a first camera-side ground terminal corresponding to the firstpower, a second camera-side power supply terminal that outputs secondpower, and a second camera-side ground terminal corresponding to thesecond power, the accessory comprises: an eighth terminal that isbrought into contact with the first camera-side clock terminal; a secondterminal that is brought into contact with the first camera-side powersupply terminal; and a third terminal that is brought into contact withthe first camera-side ground terminal, wherein a distance between theeighth terminal and the second terminal is longer than a distancebetween the third terminal and the second terminal.(18) The accessory further includes a fifth terminal that is broughtinto contact with the second camera-side ground terminal, wherein thefifth terminal is positioned between the third terminal and the eighthterminal.(19) The seventh terminal is positioned between the third terminal andthe eighth terminal.

REFERENCE SIGNS LIST

1 . . . camera system, 2 . . . camera body, 3 . . . interchangeablelens, 21 . . . body-side mount, 22 . . . body-side terminal holdingunit, 31 . . . lens-side mount, 32 . . . lens-side terminal holding unit

The invention claimed is:
 1. An accessory that can be attached to acamera body, the camera body including a first camera-side clockterminal that outputs a first clock signal, a second camera-side clockterminal to which a second clock signal is input, and a firstcamera-side power supply terminal that outputs first power, theaccessory comprising: an eighth terminal that is brought into contactwith the first camera-side clock terminal; a tenth terminal that isbrought into contact with the second camera-side clock terminal; and asecond terminal that is brought into contact with the first camera-sidepower supply terminal, wherein: a distance between the tenth terminaland the second terminal is longer than a distance between the eighthterminal and the second terminal.
 2. The accessory according to claim 1,wherein: the camera body includes a third camera-side data terminal towhich a third data signal is input; the accessory further includes aninth terminal that is brought into contact with the third camera-sidedata terminal, wherein the ninth terminal is positioned between theeighth terminal and the tenth terminal.
 3. The accessory according toclaim 1, wherein: the camera body includes a third camera-side dataterminal to which a third data signal is input, and a first camera-sidedata terminal that outputs a first data signal; the accessory furtherincludes: a seventh terminal that is brought into contact with the firstcamera-side data terminal; and a ninth terminal that is brought intocontact with the third camera-side data terminal, wherein the eighthterminal is positioned between the seventh terminal and the ninthterminal.
 4. The accessory according to claim 1, further including acontrol unit that controls driving of at least one of plurality oflenses and communication with the camera body, wherein the communicationis command communication performed using the seventh terminal and thefirst camera-side data terminal, the eighth terminal and the firstcamera-side clock terminal, and the ninth terminal and the thirdcamera-side data terminal.
 5. The accessory according to claim 1,wherein the accessory is an interchangeable lens.